Multispecies rodent cage

ABSTRACT

A rodent cage including a cage bottom having a plurality of integral side walls, a floor and an open top end. A peripheral lip extends continuously around the top end. A pair of recesses are disposed on the peripheral lip. A feeder assembly has a frame and at least one section descending therefrom. The frame has pair of flanges extending therefrom so that when the feeder assembly is disposed in the cage bottom the pair of flanges are mated with the pair of recesses, respectively. A bonnet is dimensioned in size for sealing the top end of the cage bottom. A lock is disposed on the bonnet for preventing rodents housed in the cage from displacing the bonnet from the cage bottom.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation of U.S. patent application Ser. No. 09/106,389filed on Jun. 26, 1998 U.S. Pat. No. 6,401,741.

BACKGROUND OF INVENTION

This invention relates generally to a rodent cage which may be used as astatic unit or in connection with a ventilated cage and rack system and,in particular, to a rodent cage that may be used for a variety of rodenttypes including but not limited to rats, mice, gerbils, hamsters andguinea pigs.

Ventilated cage and rack systems are well known in the art. One suchventilated cage and rack system is disclosed in U.S. Pat. No. 4,989,545,assigned to Lab Products, Inc., in which an open rack system including aplurality of shelves, each formed as an air plenum is provided. Aventilation system is connected to the rack system for ventilating eachcage in the rack.

In prior art ventilated cage and rack systems, cages of different sizesare used to accommodate rodents of different types. These sizes areselected according to Institute Laboratory Animal Resources (ILAR)guidelines which set non-binding minimums for the size and dimension ofcages for particular rodents. For example, for mice that weigh more than25 grams, a cage having a dimension of at least 15 square inches permouse is required. Similarly, rats up to 400 grams in size require acage of at least 40 square inches per rat. Similar requirements aremandated for hamsters and guinea pigs by the Animal Welfare Act (AWA).

A drawback of the prior art cages is that a variety of different cagesizes, necessary to support the different rodent types, must beinventoried and managed so that the appropriate cage size is availablefor a particular study. This problem is exacerbated in large researchfacilities, for example, the National Institute of Health (NIH), where20 to 30 different cage sizes have to be coordinated. Furthermore, eachdifferent cage size requires that the corresponding rack that supportsthe particular cage size and corresponding accessories be used. Thisforces the facility to inventory and manage a variety of different racksizes as well. Accordingly, it would be desirable to provide a singlecage size which is suitable for different rodent types therebysimplifying the maintenance of cage and rack systems.

The prior art cages include a cage bottom having four walls and a basewith an open top. A wire bar lid, that stretches across the top of thecage bottom and extends into the cage bottom, is disposed between thecage bottom and bonnet. A bonnet supporting an air filter thereon isplaced on top of the cage bottom wire bar lid thereby covering the cagebottom. The wire bar lid is constructed from stainless steel andsupports food and water in the cage while also preventing the rodents,particularly rats, from gnawing through the bonnet and damaging thefilter or escaping from the cage.

Several problems exist with the use of the wire bar lid in the prior artcage design. First, because the wire bar lid extends into the cagebottom, it creates an artificial ceiling between the cage bottom and thebonnet thereby reducing the amount of area and height available for therodents. Also the wire bar lid must be removed to provide access to theanimal requiring labor and work space for placing the lid during use.Also, the wire bar lid prevents the bonnet from sitting flush on thecage bottom thereby allowing air to either escape or enter the cagebottom over the lid wires creating a Venturi effect in a ventilated cageenvironment. Although this problem is most pronounced when rounded wirebar lids are used, it nevertheless exists even when flat rimmed wire barlids are employed. Accordingly, it is desirable to provide a rodent cagein which a wire bar lid is not required so that the usable area forrodents is maximized and ventilation to the cage is improved.

SUMMARY OF THE INVENTION

The present invention is for a rodent cage used in various rack systemsthat can support a variety of rodent types. In accordance with thepresent invention, the rodent cage includes a cage bottom having aplurality of integral side walls, a floor and an open top end. Aperipheral lip extends continuously around the top end and a pair ofrecesses are formed in the peripheral lip. A feeder assembly has a frameand at least one section descending therefrom. The frame has a pair offlanges extending therefrom so that when the feeder assembly is disposedin the cage bottom, the pair of flanges is received within therespective recesses. A bonnet is placed on the top of the cage bottomand is dimensioned and sized for sealing the cage bottom. A lock isdisposed on the bonnet for preventing rodents in the cage fromdisplacing the bonnet from the cage bottom.

Accordingly, it is an object of the present invention to provide arodent cage that can be used to house different rodent types.

Another object of the present invention is to provide a rodent cage withan efficient size for a variety of rodents.

Another object of the present invention is to provide a rodent cagehaving more useable space while protecting a filter from damage.

Yet another object of the invention is to provide a cage which reducesthe ability of rats to damage the cage by gnawing.

Still another object of the invention is to provide a simple structurefor locking the bonnet to the cage bottom.

Still other objects and advantages of the invention will in part beobvious and will in part be apparent from the specification.

The invention accordingly comprises the features of construction,combination of elements and arrangements of parts which will beexemplified in the construction here and after set fort, the scope ofthe invention will be indicated in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a fuller understanding of the invention, reference is had to thefollowing description taken in connection with the accompanyingdrawings, in which:

FIG. 1 is a perspective view of the multispecies rodent cage constructedin accordance with the present invention;

FIG. 2 is an exploded perspective view of the multispecies rodent cageconstructed in accordance with the invention;

FIG. 3 is a cross sectional view taken along line 3—3 of FIG. 1;

FIG. 4 is a cross sectional view taken along line 4—4 of FIG. 1;

FIG. 5 is a cross sectional view taken along line 5—5 of FIG. 1;

FIG. 6 is a cross sectional view taken along line 6—6 of FIG. 5;

FIG. 7 is a cross sectional view taken along line 7—7 of FIG. 1;

FIG. 8 is a cross sectional view taken along line 8—8 of FIG. 7;

FIG. 9 is a cross sectional view of a lock constructed in accordancewith invention in the unlocked position; and

FIG. 10 is a cross sectional view taken along line 10—10 of FIG. 9.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to FIGS. 1-6, there is shown a rodent cage 1 constructedin accordance with the present invention. Rodent cage 1 includes a cagebottom 3 having four integral side walls 12 and a floor 13. Cage bottom3 also includes an open top end 16. Extending continuously around topend 16 of cage bottom 3 is a peripheral lip 8 having a smooth and flatsurface. A rim 4 vertically descends from peripheral lip 8. A pair ofrecesses 35, 35′ are formed in peripheral lip 8. In an exemplaryembodiment, recess 35 is disposed in the portion of peripheral lip 8adjacent a corner of cage bottom 3 while recess 35′ is disposed in theportion of peripheral lip 8 that is opposite recess 35.

Although cage bottom 3 may be constructed from any suitable material, itis preferable that it be molded from transparent plastic so that therodents contained in cage bottom 3 can be monitored through side walls12. Also, it is preferred that cage bottom 3 have rounded cornersthereby preventing the rodents, and in particular rats, from purchasingon the corners and gnawing their way out of cage 1.

The dimension of sage bottom 3 is optimized to permit the housing ofdifferent rodent types, including mice, rats, hamster, gerbils andguinea pigs in conformance with ILAR and AWA guidelines. In a preferredembodiment, cage bottom 3 is selected to have a size of approximately 80square inches measured at the bottom of cage bottom 3 with a depth ofapproximately 7⅝ inches. Because many studies can begin housing two ratsper cage, cage bottom 3 having an area of about 80 square inches cansupport two rats of up to 400 grams each. Once the rats grow, forexample, in long-term studies, they will be placed in their ownindividual cages. Also, cage bottom 3 having an area of about 80 squareinches can accommodate either a guinea pig or at least five mice whilecomplying with ILAR and AWA guidelines. Thus, by selecting cage bottom 3having an area of about 80 square inches, a single cage 1 can be used tosupport a variety of rodent types. Accordingly, by standardizing cagebottom 3 having this dimension, a research facility will greatlysimplify the inventory and management of cages 1 and racks.

A feeder assembly, generally indicated as 23, is supported in cagebottom 3 for providing food and water to the rodents housed therein.Feeder assembly 23 includes a frame 69 having a platform portion 68.

Extending from two opposite sides of platform 68 are a pair of flanges39, 39′. Flanges 39, 39′ extend outwardly from frame 69 with flange 39disposed on one side of frame 69 and flange 39′ disposed on the oppositeside of frame 69. Flanges 39, 39′ may be either integrally formed withframe 69 or separately formed and then fixed to frame 69 thereafter.Flanges 39, 39′ are dimensioned and shaped so that when feeder assembly23 is disposed in cage bottom 3, flanges 39, 39′ are received inrecesses 35, 35′, respectively, and are flush with peripheral lip 8 ofcage bottom 3.

A lip 17 extends along a front of platform 68 which is intermediate thesides of frame 69 containing flanges 39, 39′. Lip 17 extends upward andaway from frame 69. Feeder assembly 23 is placed in cage bottom 3 sothat lip 17 extends toward the center of cage 1. In an exemplaryembodiment, lip 17 is smooth and curved to prevent rodents in cagebottom 3 from perching on lip 17 or feeder assembly 23 to either gainaccess to the food and water contained in feeder assembly 23 from aboveor from purchasing for gnawing at feeder assembly 23. Also, lip 17serves as a handle for positioning feeder assembly 23 in cage bottom 3.

A first support 52 and a second support 52′ depend from platform 68 andform open ended polygons suspended therefrom. Supports 52, 52′ havesides 56. Supports 52 and 52′ of feeder assembly 23 can be adapted tosupport either food or water for the rodents housed in cage bottom 3. Toadapt support 52 for food, a snap on food holder 37 is attached to thebottom of support 52. A skirt 73 is disposed around the circumference ofthe bottom of supports 52, 52′. Food holder 37 includes a peripheral rim71. Descending from peripheral rim 71 is a plurality of U-shaped bars 38on food holder 37. U-shaped bars 38 are spaced apart so that fooddisposed in support 52 is retained by food holder 37 but yet allows therodents in cage bottom 3 to remove the food from between U-shaped bars38 of food holder 37. Rim 71 is dimensioned to receive channel 74 andsecure rim 71 to support 52 or 52′. It also provides a flush continuoussurface eliminating purchase points and protecting the edges of skirt 73from the animal. A recess 77 is disposed on skirt 73. A lock tab 75 isdisposed on rim 71. Lock tab 75 and recess 77 are dimensioned andpositioned so that when food holder 37 is connected to support 52, locktab 75 is inserted into recess 77 thereby securing food holder 37 tosupport 52. In a preferred embodiment rim 71 is flush with the side 56of support 52 or 52′ so that rodents cannot perch on rim 71 or sides 56.In a preferred embodiment, food holder 37 is constructed from stainlesssteel so that the rodents are prevented from gnawing through food holder37 and support 52.

Either support 52 or 52′ may also be adapted to receive a water bottle21 to provide water to the rodents in cage bottom 3. To adapt support 52for water, a water bottle support 31 is secured to the bottom of support52. As with food holder 37, water bottle support 31 includes a rim 71having a recess 77 so that when rim 71 is placed about skirt 73 ofsupport 52, recess 77 mates with lock tab 75 and rim 71 fits about skirt73 so that rim 71 is flush with the sides 56 of support 52. Descendingfrom rim 71 of water bottle support 31 are four integral walls and afloor 34. The walls 36 of water bottle support 31 are inwardly offsetfrom rim 71 of water bottle support 31 thereby forming a shoulder 33between walls 36 and rim 71 around the inside circumference of waterbottle support 31. A floor 34 is supported by walls 36. Located in thecenter of floor 34 is a hole or slot 32. In a preferred embodiment,water bottle support 31 is constructed of stainless steel so that therodents in cage bottom 3 are prevented from gnawing through water bottlesupport 31 and support 52.

It is preferred that supports 52 and 52′ be constructed from transparentplastic so that the food levels in supports 52 and 52′ can be monitoredthrough side walls 12. Supports 52 and 52′ may be formed in any suitableshape including conical and rhomboidal but are preferably a roundedpolygon to prevent chewing and maximize volume. Supports 52, 52′ areradiused at the corners to sufficiently prevent chewing by the animal.Studies have shown that by way of example a radius of about 1 inch atthe top tapering to ⅞ of an inch at the bottom has been sufficient.Support 31 and feeder holder 37 may also be formed of plastic. Thecorners would be sufficiently radiused to prevent gnawing by the animal.

Because supports 52, 52′ can each hold both food or water it is possibleto double the food capacity by utilizing two feedholders 37 and a rackwatering valve (not shown). This extends the life of the study andreduces the number of times that the top must be removed.

Water bottle 21 includes a main body 24 for containing water that ispreferably dimensioned and shaped to mate with support 52. Main body 24substantially fills support 52 so that the water capacity of waterbottle 21 is maximized. It is also preferable that main body 24 beconstructed from a transparent material so that the amount of waterremaining in water bottle 21 can be monitored through side walls 12 andthe walls of supports 52, 52′. The top portion of main body 24 includesa pair of molded recesses 25 disposed on opposite sides of main body 24so that water bottle 21 may be easily gripped and removed from support52. Water bottle 21 is positioned in support 52 in a substantiallyvertical orientation so that substantially all the water stored in waterbottle 21 will drain out therefrom.

Main body 24 is tapered in a manner which forms a shoulder 22 around thecircumference of main body 24 which extends into a neck 23. As a result,when water bottle 21 is placed in support 52, shoulder 22 contacts ledge33 of support 52 thereby supporting water bottle 21 in support 52.

Neck 23 of main body 24 narrows to an opening into which a rubberstopper 29 is inserted or screw cap is placed. A tube 27 extends fromrubber stopper 29. When water bottle 21 is placed into support 52, tube27 is inserted through the hole or slot in floor 34 of water bottlesupport 31 and extends into cage bottom 3 thereby providing the rodentsin cage bottom 3 with access to the water in water bottle 21.

Top end 16 of cage bottom 3 is covered with a bonnet 14. Bonnet 14includes three parts that are connected together into one unit: a top 9,a filter 7 and a filter retainer 5. The parts of bonnet 14 are arrangedso that top 9 is in direct contact with top lip 8 of cage bottom 3,filter 7 is disposed on top 9 and filter retainer 5 is placed on topfilter 7 and is secured to top 9 thereby forming a unitary structure.

In an exemplary embodiment, top 9 is dimensioned and shaped to cover andeffectively seal top end 16 of cage bottom 3. Top 9 is formed from aresilient material, by way of example stainless steel or plasticdesigned without purchase points, so that the rodents in cage 1 areprevented from gnawing through bonnet 14 to filter 7. Top 9 is alsoperforated, having a plurality of air passages 62, across its surface sothat air can pass through top 9 into cage bottom 3. The top surface oftop 9 includes a series of cross beams 41 for supporting filter 7 awayfrom the holes separating filter 7 from access by the animals containedwithin the cage. Cross beams 41 divide the surface of top 9 into aplurality of areas 42.

Opposite cross beams 41 on the bottom surface of top 9 are a series ofreceiving portions 19. As seen in FIG. 3, receiving portions 19 aredimensioned and shaped so that when top 9 is placed on cage bottom 3containing feeder assembly 23, lip 17 is introduced in receiving portion19 that is adjacent lip 17 thereby creating a barrier to supports 52 and52′ of feeder assembly 23. In this way, rodents in cage bottom 3 areprevented by lip 17 from gaining access to the food or water in support52 from above. This also prevents access to lip 17 by the animal,preventing chewing of lip 17 itself. Also, because top 9 will not beproperly seated on cage bottom 3 unless lip 17 is mated with receivingportion 19, this ensures that feeder assembly 23 is properly positionedin cage bottom 3 before cage 1 is closed by bonnet 14.

Along the periphery of top 9 is a descending rim 18. Disposed on rim 18and protruding from top 9 are a plurality of detents 11. Extending fromdescending rim 18 along the periphery of top 9 is a horizontal flange20. Vertically descending from flange 20 is a skirt 10. When top 9 isplaced on cage bottom 3, flange 20 is seated flush on peripheral lip 8of cage bottom 3 thereby minimizing the amount of air that flows outfrom the perimeter of top 9 thus maximizing the air flowing throughfilter 7. Also, because flanges 39, 39′ of feeder assembly 23 arepositioned within recesses 35, 35′ and are flush with peripheral lip 8,top 9 forms a seal with cage bottom 3 along the entire periphery of cagebottom 3. Furthermore, skirt 10 which extends around rim 4 improves theseal formed between top 9 and cage bottom 3 by creating a circuitouspath for air travel between the interior of cage 1 and the outsidethereby inhibiting air from entering or leaving cage 1 at this junctionpoint. In a exemplary embodiment, an additional sealing member, forexample silicon or rubber material, may be applied to either or bothflange 20 or peripheral lip 8 thereby providing an O-ring type sealfurther limiting air passage via this route.

Filter 7 is placed on top of top 9 and is supported by cross beams 41away from areas 42 to prevent contact with rodents. Filter retainer 5 isplaced on top of filter 7 and is dimensioned and shaped so as to coverthe entire filter 7. Filter retainer 5 is also perforated, containingholes 64 throughout its surface thereby allowing air to pass throughfilter 7. Protruding from the bottom surface of filter retainer 5 andextending around the bottom surface of filter retainer 5 is a track 6.When filter retainer 5 is mounted on filter 7, track 6 compresses filter7 against the top surface of top 9 thereby securing filter 7 in placeand preventing air from leaking past the filter in any direction.

A descending border 54 extends from the outer periphery of filterretainer 5. A plurality of windows 13 are formed in border 54 of filterretainer 5. Windows 13 are dimensioned and positioned so that whenfilter retainer 5 is mounted on top of filter 7, windows 13 receivedetents 11 of top 9, respectively, thereby securing filter retainer 5 totop 9. In this way, filter retainer 5, filter 7 and top 9 of bonnet 14form a unitary structure.

Top 9 may be made of plastic. To further prevent the animal fromperching on top 9, air passages 62 are radiused to provide a smoothcurved surface facing the animal. Passages 62 are also dimensioned toprevent the animal's nose, claws or teeth from reaching the filter.

Reference is now made to FIGS. 7-10. A lock 15 is mounted on skirt 10 oftop 9. Lock 15 includes a channel-shaped lock housing 55 that is fixedto skirt 10. Lock spring 47, disposed in housing 55, includes a visualalert 45 portion upon which is mounted a visual alert 46, a securingportion 48, a tension portion 50 and a biasing portion 65. Lock spring47 is positioned in housing 55 so that biasing portion 65 is adjacentthe center of housing 55. Lock spring 47 is secured to housing 55 byconnecting securing portion 48 to the back wall of housing 55 using anysuitable technique, such as welding or gluing. In an exemplaryembodiment, lock spring is constructed from a hard, resilient material,such as a strip of metal, and is shaped so that visual alert portion 45and tension portion 50 are spaced away from the back wall of housing 55.Mounted in the center of housing 55 is a pivot 57. Lock spring 47 is ofa sufficient length so that biasing portion 65 extends to a pointintermediate pivot 57 and the back wall of housing 55.

A lock bar 53 is disposed in housing 55 and includes an arm 59 and acurved portion 61 at an end of arm 59. Lock bar 53 is rotatably mountedon pivot 57 at an end of arm 59 that is adjacent curved portion 61. Lockbar 53 is of a sufficient length so that a portion of arm 59 extendsoutside housing 55 when lock 15 is in either the locked or unlockedposition so that lock bar 53 may be easily gripped and rotated. A lockflange 49 extends horizontally from a lower edge of curved portion 61 oflock bar 53.

When lock bar 53 is rotated away from lock spring 47, lock flange 49faces away from cage bottom 3 and lock 15 is in the unlocked portion. Inthis position, biasing portion 65 is biased against the portion of lockbar 53 that is adjacent pivot 57 thereby keeping lock bar 53 fromrotating towards lock spring 47 and keeping lock 15 in the unlockedposition. In the unlocked position, visual alert 45, preferably areadily visible member such as a yellow tab, is exposed indicating thatlock 15 is unlocked.

When lock bar 53 is rotated to lock spring 47, lock flange 49 isinserted into a notch 51 disposed in cage bottom 3 thereby securing top9 to cage bottom 3. While in the locked position, biasing portion 65 isbiased against curved portion 61 of lock bar 53 at a point that isvertically adjacent to lock flange 49 thereby keeping lock bar 53 fromrotating away from lock spring 47 and keeping lock 15 in the lockedposition. Also, because lock bar 53 covers visual alert 45 when lock bar53 is rotated towards lock spring 47 into the locked position, thelocked cage 1 are readily distinguishable from the unlocked cages 1.

Rodent cage 1 constructed in accordance with the present inventionoffers many advantages over prior art cages. First, because thedimension of cage bottom 3 is optimally selected to have a size of 80square inches, cage 1 can be used for mice, rats, hamsters and guineapigs while confirming to ILAR guidelines. By providing a universal cagesize, the need for storing and managing different size cages anddifferent size racks to support the different cage sizes is eliminated.Also, because feeder assembly 23 is modular and adaptable by snapping oneither water bottle support 31 or food holder 37, as needed to supportthe varying eating requirements of the different studies and rodents,storage and maintenance of feeder assembly 23 is greatly simplified.

The durability and reliability of cage 1 of the present invention isalso improved. Also, rounded lip 17, extending from feeder assembly 23,which is received by receiving portion 19 of top 9, prevents rodentsfrom perching and accessing food in feeder assembly 23 from above. Byradiusing supports 52, 52′ of feeder 23, eliminates purchase points onthe feeder. Furthermore, by mounting either water bottle support 31 orfood holder 37, both made of stainless steel, to the bottom of supports52, 52′ of feeder assembly 23, the rodents are prevented from gnawingthrough the bottom of feeder assembly 23. Also, by forming top 9 fromstainless steel, or radiusing passages 62 in plastic the rodents will beunable to gnaw through bonnet 14. Finally, by including lock 43 onbonnet 14, the rodents housed in cage bottom 3 will be unable todisplace bonnet 14 and escape.

Furthermore, the ventilation of the cage is greatly improved byeliminating the wire lid that was used in prior art cages and reducingthe Venturi effect therein. Also, because flanges 39, 39′ are mountedflush in feeder recesses 35, 35′, respectively, bonnet 14 forms animproved seal with cage bottom 3 preventing air from passing throughthis junction and forcing more air through filter 7. In addition, byproviding a sealing member such as rubber or silicon along the junctionbetween top 9 and cage bottom 3, the seal is further improved andventilation through filter 7 is increased.

Cage 1 constructed in accordance with the present invention is alsoeasier to use than the prior art cages. First, because cage bottom 3 isconstructed from transparent material, visibility of the rodents in cagebottom 3 is improved. Also, by inserting feeder assembly 23 at the rearof cage bottom 3, visibility and access to the animals is improved.Furthermore, because sections 52, 52′ of feeder assembly 23 isconstructed from clear plastic, inspection of the food and water levelsin feeder assembly 23 is facilitated without having to remove bonnet 14.By supporting the water bottle in a substantially vertical position, notonly does substantially all of the liquid flow from the bottle, but thebottle utilizes less cage volume than if oriented at an angle. Also, byusing water bottle 21 having molded recesses 25, the insertion andremoval of water bottle 21 from section 52 is simplified and eliminatingthe step of separately removing the lid and setting it aside. Inaddition, because bonnet 14 is formed as a unitary structure, top 9,filter 7 and filter retainer 5 may be removed from cage bottom 3 in onepiece thereby easing access to the interior of cage bottom 3. Inaddition, because filter retainer 5 may be removed from top 9 while top9 is still secured to cage bottom 3, filter 7 may be inspected andchanged while keeping the rodents securely locked in cage bottom 3.Finally, visual alert 45 of lock 43 simplifies the determination ofwhich cages 1 are in the unlocked position.

It will thus be seen that the objects set forth above, and those madeapparent from the preceding description, are efficiently obtained and,because certain changes may be made in the above constructions withoutdeparting from the spirit and scope of the invention, it is intendedthat all matter contained in the above description are shown in theaccompanying drawings shall be interpreted as illustrative and not in anlimiting sense.

It is also to be understood that the following claims are intended tocover all the generic and specific features of the invention hereindescribed, and all statements of the scope of the invention which, as amatter of language, might be said to fall therebetween.

What is claimed is:
 1. A rodent cage, comprising: a cage bottom having a plurality of integral side walls, a floor and an open top end, and a peripheral lip extending continuously around said top end; a feeder assembly having a frame and at least one support descending from said frame, said frame having first and second flanges extending therefrom so that when said feeder assembly is disposed in said cage bottom said flanges are supported by only two opposed walls of said walls; and a bonnet dimensioned and sized for sealing said open top end of said cage bottom being comprised of three elements a top element, a filter element and a filter retainer element; and wherein said at least one support is dimensioned to support a water bottle in a substantially vertical position relative to said frame; wherein said filter retainer element has pressing means to secure said filter element in place against the upper surface of said top element; wherein said top element has a bottom side and a receiving portion formed therein, said feeder assembly further comprising an upwardly extending lip disposed on said frame, wherein said lip is received by said receiving portion thereby preventing the rodents from accessing said at least one support from above; wherein said cage bottom is constructed of plastic.
 2. The rodent cage of claim 1, wherein said floor of said cage bottom has an area of approximately 80 square inches.
 3. The rodent cage of claim 1, wherein said frame of said feeder assembly has at least a second support descending from said frame.
 4. The rodent cage of claim 1, wherein said at least one support forms a polygon.
 5. The rodent cage of claim 1, wherein said feeder assembly is constructed from transparent plastic.
 6. The rodent cage of claim 1, wherein said support has an open lower end and further comprising a snap on bottom, said snap on bottom being selectively connected to said lower end of said at least one support.
 7. The rodent cage of claim 6, wherein said snap on bottom is a food container.
 8. The rodent cage of claim 6, wherein said snap on bottom is a water bottle support.
 9. The rodent cage of claim 1, further comprising a water bottle disposed on said at least one support.
 10. The rodent cage of claim 9, wherein said water bottle further comprises a main body, said main body having a pair of molded recesses for inserting said water bottle into and removing said water bottle from said at least one support.
 11. The rodent cage of claim 10, wherein said main body and said at least one support are substantially the same shape.
 12. The rodent cage of claim 1, wherein said top has a surface, said surface being perforated for allowing air to pass to and from said cage bottom.
 13. The rodent cage of claim 1, wherein said top has a perimeter and further comprises a vertical portion descending from said perimeter of a surface, and a border horizontally extending from said vertical portion, wherein when said top is placed on said cage bottom, said border contacts said peripheral lip thereby substantially sealing said cage bottom.
 14. The rodent cage of claim 13, wherein said cage bottom further comprises a rim vertically descending from said peripheral lip, and said top further comprises a skirt vertically descending from said border, wherein when said top is placed on said cage bottom, said skirt extends around said rim thereby creating a circuitous path for the movement of air from inside said cage bottom to outside said cage bottom.
 15. The rodent cage of claim 1, wherein said top element is constructed from stainless steel.
 16. The rodent cage of claim 1, wherein said top has a plurality of cross beams and further comprises a filter disposed on said plurality of cross beams for filtering air entering said cage bottom through said top element.
 17. The rodent cage of claim 16, wherein said filter retainer element is disposed on said filter, said filter retainer element having a perforated surface for allowing air to pass to and from said cage bottom.
 18. The rodent cage of claim 17, wherein said filter retainer has a descending border, said descending border of said filter retainer element having a plurality of windows, said top further comprising a plurality of detents protruding from a rim of said top element, said windows receiving said detents to secure said filter retainer to said top.
 19. The rodent cage of claim 17, wherein said filter retainer has a bottom side, a track protrudes from said bottom side of said filter retainer and compresses said filter against said top for securing said filter in place maintaining integrity of filtered air entering into the cage.
 20. The rodent cage of claim 1, further comprising a lock for locking said top to said cage bottom.
 21. The rodent cage of claim 20, wherein said lock comprises a lock bar, said lock bar rotatable from an unlocked position to a locked position.
 22. The rodent cage of claim 21, wherein said lock further comprises a visual alert, wherein when said lock is in said unlocked position said visual alert is visible and when said lock is in said locked position, said visual alert is not visible.
 23. The rodent cage of claim 1, wherein said pressing means is comprised of a track protruding from the bottom surface of said filter retainer.
 24. A cage level barrier rodent cage, comprising: a cage bottom having a plurality of integral side walls, a floor and an open top end, and a peripheral lip extending continuously around said open top end; a feeder assembly having a frame and at least one support descending from said frame, said frame having first and second flanges extending therefrom, said flanges being supported by said cage bottom on a portion of two opposed integral walls; and, a bonnet dimensioned and sized for sealing said open top end of said cage bottom, said bonnet including a filter element, said bonnet protecting said filter element without a wire bar lid, said bonnet being comprised of two additional elements a top element and a filter retainer element; and wherein said at least one support is dimensioned to support a water bottle in a substantially vertical position relative to said frame; wherein said top element has a bottom side and a receiving portion formed therein, said feeder assembly further comprising an upwardly extending lip disposed on said frame, wherein said lip is received by said receiving portion thereby preventing the rodents from accessing said at least one support from above; wherein said filter retainer element has pressing means to secure said filter element in place against the upper surface of said top element; and wherein said cage bottom is constructed of plastic.
 25. The cage level barrier level rodent cage of claim 24, wherein said floor of said cage bottom has an area of approximately 80 square inches.
 26. The cage level barrier rodent cage of claim 24, further comprising a water bottle disposed in said at least one support.
 27. The cage level barrier rodent cage of claim 24, wherein said bonnet includes said top element capable of covering said top end of said cage bottom.
 28. The cage level barrier rodent cage of claim 27, wherein said top has a surface, said surface being perforated for allowing air to pass to and from said cage bottom.
 29. The cage level barrier rodent cage of claim 28, wherein said top has a perimeter and further comprises a vertical portion descending from said perimeter of said surface, and a border horizontally extending from said vertical portion, wherein when said top is placed on said cage bottom, said border contacts said peripheral lip thereby substantially sealing said cage bottom.
 30. The cage level barrier rodent cage of claim 27, further comprising a lock for locking said top to said cage bottom.
 31. The rodent cage of claim 24, wherein said pressing means is comprised of a track protruding from the bottom surface of said filter retainer. 